An example of prior-art bead forming apparatus of the type above specified is disclosed in Japanese Patent Publication No. 57-26943. The bead forming apparatus therein taught is constructed to have a bead forming element wound on a tire ply preliminarily wrapped round a drum adapted to form a green tire. The drum is formed with circumferential grooves adjacent the opposite axial ends of the drum and with recesses respectively crossing the grooves. Each of the recesses is open in the peripheral and end walls of the drum and is deeper than the circumferential grooves. Means are provided to feed bead forming elements in such a manner that each of the bead forming elements has its leading end located in each of the recesses through the tire ply wrapped round the drum. Each bead forming element is retained at its leading end in each of the recesses by retaining means rotatable with the drum. The drum is then driven for rotation to have the bead forming elements wound on the tire ply. After a predetermined length of bead forming element is wound on the drum adjacent each axial end of the drum, the bead forming element is liberated from the recess and has its trailing end retained to the resultant wire bead in the vicinity of the initial leading end of the bead forming element.
In order to feed a bead forming element to the drum in a prior-art bead forming apparatus of this type, suitable pinch-off means is provided to have the bead forming element gripped at its leading end. The pinch-off means is driven to move toward the drum together with the bead forming element thereby gripped. The provision of such pinch-off means results in intricate construction of the bead forming apparatus as a whole. A problem further arises from the use of the pinch-off means in that the bead forming element tends to be contaminated with the lubricant which must be applied to the pinch-off means.
After a tire bead is formed on the drum, the bead forming element is cut from the tire bead by suitable cutting means. The cutting means and the means to drive the retaining means provided in the above described prior-art bead forming apparatus are located at considerable distances from the drum, this resulting in large-sized overall construction of the apparatus. The prior-art bead forming apparatus is further required to use means such as an adhesive tape or an adhesive compound to have the trailing end portion of the bead assuredly retained to the body of the bead so as to prevent the trailing portion from recoiling.
A prime object of the present invention is to provide an improved bead forming apparatus which is free from these problems which have thus far been inherent in a prior-art bead forming apparatus of the described nature.